Super Duplex/

Super Duplex

Super Duplex Stainless Steel grades at a glance with ASTM specification and equivalent chart

Super duplex stainless steel belongs to a distinct category within the duplex steel family, characterised by its composition of chromium, molybdenum, and nickel alloys. This unique alloy exhibits a dual nature, combining the strengths of ferritic and austenitic steel while offering corrosion resistance. The three primary duplex groups are the standard duplex, super duplex, and lean duplex. Super duplex stands out for its superior pitting corrosion resistance, with grades ranging from EN1.4410 to hyper duplex variants with PREN numbers exceeding 45. The PREN number signifies composition percentages and corrosion resistance. Prices for super duplex steel vary among suppliers, and we provide a competitive price list for our products. Various applications in the oil and gas, chemical, marine, and desalination industries leverage different grades, with nitrogen addition enhancing corrosion resistance. Although tungsten may be used for intermetallic phases, higher quantities can impact material processing. Despite challenges, the exceptional properties of super duplex make it suitable for diverse applications, including piping systems in desalination plants, fuel systems, and the chemical and food processing industries. Super duplex steel suppliers offer sheets, plates, pipes, fittings, and accessories tailored to customer needs.

Super Duplex Steel Equivalent

Duplex 2707 HDS32707
Duplex 2507S32750X 2 CrNiMoN 25 7 423281.4410

Super Duplex Steel Grades

2507 Super Duplex AlloyUNS S32760/ S32750/ S32550/ S39274
Super Duplex 4501
UR52N+UNS S32550
Zeron 100UNS S32760
Ferralium 255UNS S32550

Super Duplex Steel ASTM Grades

GradeBarPlate, sheet and stripSeamless / welded tube and pipeFlangesPipe FittingsForgings
Duplex 2707 HDASTM A789/ A790, SA790
Duplex 2507ASTM A479, SA479
EN 10088-3
ASTM A240 SA240
EN 10088-2
ASTM A789; A790, SA790ASTM A182, SA182ASTM A182, SA182
ASTM A815/ SA815
ASTM A182/ SA182
Duplex 2304EN 10088-3ASTM A240, SA240
EN 10088-2
ASTM A789; A790, SA790
EN 10216-5
EN 10088-3*

Super Duplex Steel Specification

GradeUNSDuplex Industry Specifications
2507 Duplex SteelUNS S32750ASTM A182 F53, A240/ SA240, A276 / SA276, A479, A789, A790, A815, A928, A988
SAE J405
 UNS S32760ASTM A182 F55, A240 / SA240, A276/ SA276, A314, A473, A479, A789, A790, A815, A928, A988
SAE J405
International identifiersSUS 329J3L, S31803, SS2377, ASTM A182 F51, STS329J3 LTP, AISI 318 LN, Z3CND22-05Az

Super Duplex Steel Applications

  • Solar Power
  • Storage tanks
  • Building and construction
  • Water Desalination
  • LNG (Liquefied Natural Gas)
  • Biofuels plants
  • Water transmission pipes
  • Pressure vessels, reactor tanks and heat exchangers
  • Desalination and seawater systems
  • Rotors, impellers and shafts in industrial equipment
  • Pulp and paper plants
  • Phosphoric acid production system
  • Absorber towers, FGD systems for air pollution control
  • Food, oil and gas, mining and architectural applications

Super Duplex Steel Composition

24.0-26.06.0-8.03.0-5.0.24-.320.020 Max0.50 Max0.030 Max1.20 Max0.80 Max0.035 MaxBalance

Super Duplex Steel Properties

.2% Yield Strength, ksi MinimumUltimate Tensile Strength, ksi Minimum% Elongation Min. 

Super Duplex Stainless Steel Temperature Limits

UNS N° GradeEN N°Hot FormingTemperature RangeMinimum Soaking Temperature
S323041.43621150-950 Deg C980 Deg C
S322051.44621230 -950 Deg C1040 Deg C
S327501.44101235-1025 Deg C1050 Deg C
S325201.45071230-1000 Deg C1080 Deg C
S327601.45011230-1000 Deg C1100 Deg C

Benefits & Features of Super Duplex Steel

  • High weldability
  • Very high resistance to pitting and crevice corrosion
  • High resistance to general corrosion in acids
  • Excellent resistance to erosion corrosion
  • Excellent resistance to corrosion fatigue
  • Good mechanical strength
  • Excellent resistance to stress corrosion cracking (SCC) in chloride bearing environments


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